This invention relates generally to wellbore casings, and in particular to wellbore casings that are formed using expandable tubing.
Conventionally, when a wellbore is created, a number of casings are installed in the borehole to prevent collapse of the borehole wall and to prevent undesired outflow of drilling fluid into the formation or inflow of fluid from the formation into the borehole. The borehole is drilled in intervals whereby a casing which is to be installed in a lower borehole interval is lowered through a previously installed casing of an upper borehole interval. As a consequence of this procedure the casing of the lower interval is of smaller diameter than the casing of the upper interval. Thus, the casings are in a nested arrangement with casing diameters decreasing in downward direction. Cement annuli are provided between the outer surfaces of the casings and the borehole wall to seal the casings from the borehole wall. As a consequence of this nested arrangement a relatively large borehole diameter is required at the upper part of the wellbore. Such a large borehole diameter involves increased costs due to heavy casing handling equipment, large drill bits and increased volumes of drilling fluid and drill cuttings. Moreover, increased drilling rig time is involved due to required cement pumping, cement hardening, required equipment changes due to large variations in hole diameters drilled in the course of the well, and the large volume of cuttings drilled and removed.
Conventionally, at the surface end of the wellbore, a wellhead is formed that typically includes a surface casing, a number of production and/or drilling spools, valving, and a Christmas tree. Typically the wellhead further includes a concentric arrangement of casings including a production casing and one or more intermediate casings. The casings are typically supported using load bearing slips positioned above the ground. The conventional design and construction of wellheads is expensive and complex.
The present invention is directed to overcoming one or more of the limitations of the existing procedures for forming wellbores and wellheads.
According to one aspect of the present invention, an apparatus for radially expanding a tubular member is provided that includes a support member, a tubular member coupled to the support member, a mandrel movably coupled to the support member and positioned within the tubular member, an annular expansion cone coupled to the mandrel and movably coupled to the tubular member for radially expanding the tubular member, and a lubrication assembly coupled to the mandrel for supplying a lubricant to the annular expansion cone that includes a sealing member coupled to the annular member, a body of lubricant positioned in an annular chamber defined by the space between the sealing member, the annular member, and the tubular member, and a lubrication supply passage fluidicly coupled to the body of lubricant and the annular expansion cone for supplying a lubricant to the annular expansion cone.
According to another aspect of the present invention, an apparatus for radially expanding a tubular member is provided that includes a tubular support member defining an internal passage, an expandable tubular member defining an internal passage for receiving the tubular support member coupled to the tubular support member, a mandrel movably coupled to the tubular support member and positioned within the expandable tubular member defining an internal passage for receiving the tubular support member comprising an external flange, a lubrication fitting defining an internal passage for receiving an end of the mandrel and a first lubrication supply passage comprising an external flange and a lubrication injection fitting for injecting lubricant into the first lubrication supply passage coupled to the end of the mandrel, a resilient lubrication packing sleeve defining a passage for receiving the lubrication fitting coupled to the lubrication fitting proximate the external flange of the lubrication fitting, an annular body of lubricant positioned between the resilient lubrication packing sleeve, the external flange of the mandrel, the lubrication fitting, and the the expandable tubular member, a second lubrication supply passage defined between the lubrication fitting and the mandrel fluidicly coupled to the first lubrication supply passage and the annular body of lubricant, a reversible annular expansion cone defining a passage for receiving the mandrel comprising a plurality of outer conical surfaces coupled to the mandrel proximate the external flange of the mandrel, and a third lubrication supply passage defined between the external flange of the mandrel and the expandable tubular member fluidicly coupled to the annular body of lubricant for supplying lubricant to the interface between the annular expansion cone and the expandable tubular member.